[PATCH 2/2] autoconf: Properly quote logged command line

We were previously logging the wrong command line if the user
invoked any argument with spaces, making it difficult to
re-invoke configure with the same complex arguments. To reproduce,
open any autoconf-using project and run:

$ ./configure FLAGS='foo bar' >/dev/null && grep -m1 /configure config.log
  $ ./configure FLAGS=foo bar

Now we get the expected output:
  $ ./configure 'FLAGS=foo bar'

(Okay, it would be prettier as FLAGS='foo bar' in the output, by
delaying the opening ' until after the first non-alphanumeric or =,
but that is more expensive to produce, and makes no difference to
shell parsing of the pasted line.)

* lib/autoconf/general.m4 (_AC_INIT_CONFIG_LOG): Use _AS_INVOCATION.
* lib/autoconf/status.m4 (_AC_OUTPUT_CONFIG_STATUS): Likewise.
Reported by Kevin Brubeck Unhammer <[email protected]>

Signed-off-by: Eric Blake <[email protected]>
---

I wonder if it would also be worth updating these two logging points
to include the output of 'date' as a (rough) timestamp of when the
recorded invocation started.

 lib/autoconf/general.m4 | 3 ++-
 lib/autoconf/status.m4  | 3 ++-
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/lib/autoconf/general.m4 b/lib/autoconf/general.m4
index ef6285d..bac9fcd 100644
--- a/lib/autoconf/general.m4
+++ b/lib/autoconf/general.m4
@@ -1183,6 +1183,7 @@ fi])dnl
 m4_define([_AC_INIT_CONFIG_LOG],
 [m4_divert_text([INIT_PREPARE],
 [m4_define([AS_MESSAGE_LOG_FD], 5)dnl
+_AS_INVOCATION
 cat >config.log <<_ACEOF
 This file contains any messages produced by compilers while
 running configure, to aid debugging if configure makes a mistake.
@@ -1191,7 +1192,7 @@ It was created by m4_ifset([AC_PACKAGE_NAME], [AC_PACKAGE_NAME ])dnl
 $as_me[]m4_ifset([AC_PACKAGE_VERSION], [ AC_PACKAGE_VERSION]), which was
 generated by m4_PACKAGE_STRING.  Invocation command line was

-  $ $[0] $[@]
+  $as_invocation

 _ACEOF
 exec AS_MESSAGE_LOG_FD>>config.log
diff --git a/lib/autoconf/status.m4 b/lib/autoconf/status.m4
index 308d3d8..f692b6d 100644
--- a/lib/autoconf/status.m4
+++ b/lib/autoconf/status.m4
@@ -1334,6 +1334,7 @@ cat >>$CONFIG_STATUS <<\_ACEOF || ac_write_fail=1
 [#] Save the log message, to keep $[0] and so on meaningful, and to
 # report actual input values of CONFIG_FILES etc. instead of their
 # values after options handling.
+_AS_INVOCATION
 ac_log="
 This file was extended by m4_ifset([AC_PACKAGE_NAME], [AC_PACKAGE_NAME ])dnl
 $as_me[]m4_ifset([AC_PACKAGE_VERSION], [ AC_PACKAGE_VERSION]), which was
@@ -1343,7 +1344,7 @@ generated by m4_PACKAGE_STRING.  Invocation command line was
   CONFIG_HEADERS  = $CONFIG_HEADERS
   CONFIG_LINKS    = $CONFIG_LINKS
   CONFIG_COMMANDS = $CONFIG_COMMANDS
-  $ $[0] $[@]
+  $as_invocation

 on `(hostname || uname -n) 2>/dev/null | sed 1q`
 "
-- 
2.9.3